Eating a nutritionally adequate diet is possible without wrecking long-term health, the planet, or the pocket – Authors' reply
Authors: Ty Beal, Flaminia Ortenzi
Journal: The Lancet Planetary Health (2023)

Marco Springmann1Springmann M Eating a nutritionally adequate diet is possible without wrecking long-term health, the planet, or the pocket.Lancet Planet Health. 2023; (published online June 8.)https://doi.org/10.1016/S2542-5196(23)00129-8Google Scholar proposes how to eat a nutritionally adequate diet without wrecking long-term health, the planet, or the pocket.1Springmann M Eating a nutritionally adequate diet is possible without wrecking long-term health, the planet, or the pocket.Lancet Planet Health. 2023; (published online June 8.)https://doi.org/10.1016/S2542-5196(23)00129-8Google Scholar We agree on this goal but are concerned that Springmann does not acknowledge important flaws in the EAT–Lancet's adequacy assessment, which we find lead to the promotion of a diet that is inadequate in some micronutrients.2Beal T Ortenzi F Fanzo J Estimated micronutrient shortfalls of the EAT–Lancet planetary health diet.Lancet Planet Health. 2023; 7: e233-e237Summary Full Text Full Text PDF PubMed Scopus (0) Google Scholar Instead of addressing these flaws, Springmann uses the same approach to estimate the effects of a hypothetical, micronutritionally adequate, diet in our Viewpoint on long-term health, the planet, and the pocket. However, our Viewpoint clarifies that this diet was not optimal for these outcomes: “these modifications are intended to illustrate relatively feasible dietary shifts that help achieve nutrient adequacy but are not intended to optimally minimise non-communicable disease risk, environmental effects, or unaffordability.” We hope future efforts to design a planetary health diet address the limitations of the EAT–Lancet's adequacy assessment. For example, it is important to use the latest evidence on recommended nutrient intakes3Allen LH Carriquiry AL Murphy SP Perspective: proposed harmonized nutrient reference values for populations.Adv Nutr. 2020; 11: 469-483Summary Full Text Full Text PDF PubMed Scopus (54) Google Scholar and ensure the diet is adequate for all, especially women of reproductive age who need more iron. Two flaws are particularly important. First, the report does not mention the assumed iron bioavailability used, which could range from 5% to 18% depending on diet type.3Allen LH Carriquiry AL Murphy SP Perspective: proposed harmonized nutrient reference values for populations.Adv Nutr. 2020; 11: 469-483Summary Full Text Full Text PDF PubMed Scopus (54) Google Scholar The report should indicate what iron bioavailability was used. The more plant-based a diet is the lower the iron bioavailability. Second, zinc was assumed to have moderate bioavailability. The high amount of phytate in the EAT–Lancet diet (>2400 mg) indicates zinc has low bioavailability (defined by an unrefined diet containing >1200 mg of phytate).3Allen LH Carriquiry AL Murphy SP Perspective: proposed harmonized nutrient reference values for populations.Adv Nutr. 2020; 11: 469-483Summary Full Text Full Text PDF PubMed Scopus (54) Google Scholar Phytate binds to minerals and reduces their absorption. Iron and zinc were the two most limiting micronutrients when designing a hypothetical micronutrient adequate diet, so choice of bioavailability substantially affects which foods are needed for adequacy. We support cautious global modelling of the effects of diets on health, environment, and affordability, with proper iron and zinc bioavailability adjustments. But we worry about overusing and overtrusting these models, which have low-quality data, high uncertainty, and many limitations and assumptions. For example, models disagree on what people eat and how it affects their health.4Beal T Herforth A Sundberg S Hess SY Neufeld LM Differences in modelled estimates of global dietary intake.Lancet. 2021; 397: 1708-1709Summary Full Text Full Text PDF PubMed Google Scholar, 5Lescinsky H Afshin A Ashbaugh C et al.Health effects associated with consumption of unprocessed red meat: a burden of proof study.Nat Med. 2022; 28: 2075-2082Crossref PubMed Scopus (16) Google Scholar Springmann suggests our hypothetical micronutrient adequate diet contains 57% more beef than global average intake. But using the Global Dietary Database,6Miller V Reedy J Cudhea F et al.Global, regional, and national consumption of animal-source foods between 1990 and 2018: findings from the Global Dietary Database.Lancet Planet Health. 2022; 6: e243-e256Summary Full Text Full Text PDF PubMed Scopus (25) Google Scholar we found it contains much less beef than global average intake. Further, the Global Burden of Disease study authors changed their view on risk of unprocessed red meat consumption twice in recent years based on model changes and assumptions.5Lescinsky H Afshin A Ashbaugh C et al.Health effects associated with consumption of unprocessed red meat: a burden of proof study.Nat Med. 2022; 28: 2075-2082Crossref PubMed Scopus (16) Google Scholar Furthermore, models assessing planetary health should also consider livelihoods, culture, and preferences. We suggest global modelling of the effects of diets can be an important yet modest part of a wider evidence base for achieving planetary health. We declare no competing interests. Estimated micronutrient shortfalls of the EAT–Lancet planetary health dietUnhealthy diets are a major contributor to the global burden of disease, and food systems cause substantial environmental destruction. To lay out how to achieve healthy diets for all, within planetary boundaries, the landmark EAT–Lancet Commission proposed the planetary health diet, which includes a range of possible intakes by food group and substantially restricts the intake of highly processed foods and animal source foods globally. However, concerns have been raised about the extent to which the diet provides adequate essential micronutrients, particularly those generally found in higher quantities and in more bioavailable forms in animal source foods. Full-Text PDF Open AccessEating a nutritionally adequate diet is possible without wrecking long-term health, the planet, or the pocketTy Beal and colleagues1 are right to point to the differentiated nutrient needs for women and men. As part of the EAT–Lancet Commission on Healthy Diets from Sustainable Food Systems, we undertook analyses of nutrient adequacy based on population-level recommendations that contain the special needs of all demographic groups, including men and women of different ages and stages in their reproductive life.2,3 These population-level analyses allow and account for changes in intake for different demographic groups, and separate analyses for these groups can further help for dietary planning and informing policy responses. Full-Text PDF Open Access